A lamp power assembling structure and method, the lamp power assembling structure is installed indoors and is connected an indoor power source, and includes a lamp power seat and a lamp fixing seat. The lamp power seat has a first power connector for connecting to the indoor power source and two sliding trenches. Each sliding trench has an arced channel and an enlarged hole formed at an end of the arced channel. The lamp fixing seat has a second power connector corresponding to the first power connector and two fasteners separately corresponding to the two enlarged holes. The two fasteners are separately inserted into the two enlarged holes, and the lamp fixing seat is rotated about the first and second power connectors so as to make the two fasteners separately to be engaged with the arced channels to fix the lamp fixing seat to the lamp power seat.